(a) Field of the Invention
The present invention relates to a fuel cell system, and more particularly, to a reformer burner and a reformer using the same.
(b) Description of the Related Art
As is well known, a fuel cell is an electricity generating system for directly converting chemical reaction energy of oxygen and hydrogen contained in a fuel of a hydrocarbon material, such as methanol, ethanol, and natural gas, into electrical energy.
According to types of electrolyte used for the fuel cells, the fuel cells can be classified into phosphate fuel cells, molten carbonate fuel cells, solid-sate oxide fuel cells, polymer electrolyte fuel cells, and alkali fuel cells. These fuel cells are all operated on about the same principle, but are different from each other in terms of fuel types, operating temperatures, catalysts, electrolytes, and the like.
A polymer electrolyte membrane fuel cell (PEMFC) has been recently developed to have excellent output characteristics, low operation temperature, and fast starting and response characteristics in comparison with the other types of fuel cells. In addition, the PEMFC advantageously has a wide range of applications including a mobile power source for vehicles, a distributed power source for homes or buildings, and a small-size power source for electronic apparatuses.
The PEMFC system includes a stack, a reformer, a fuel tank, and a fuel pump. The stack constitutes a main body of the fuel cell, and the fuel pump supplies the fuel in the fuel tank to the reformer. The reformer reforms the fuel to generate a reforming gas including hydrogen and supplies the reforming gas to the stack.
In the stack, an electro-chemical reaction of the hydrogen supplied from the reformer and oxygen separately supplied to the stack occurs, so that electrical energy is generated.
In the fuel cell system having the aforementioned construction, the reformer generates the hydrogen from the fuel through a chemical catalytic reaction using thermal energy. The reformer includes a burner for generating the thermal energy and a reforming reaction unit for generating the hydrogen gas through the reforming catalytic reaction using the thermal energy. The burner has a structure for generating the thermal energy through an oxidation reaction of the fuel and the air by using an oxidation catalyst in the main body.
In a conventional reformer, the burner and the reforming reaction unit are disposed in a distributed manner to transfer the thermal energy generated from the burner to the reforming reaction unit. Therefore, in the conventional reformer, a thermal (or heat) transfer between the burner and the reforming reaction unit is needed to be performed. As a result, there is a problem in that a reaction starting time of the reforming reaction unit is delayed. In addition, there is another problem in that a performance and a reaction efficiency of the reformer deteriorate due to a temperature gradient from the burner to the reforming reaction unit.